MAG-BOARD
The MAG-BOARD is the central electronics platform for building DIY fluxgate magnetometer and gradiometer systems with FG-3+ sensors. It is an ESP32-based board that handles sensor reading, display output, user interface, and data communication.
It is the core component of the Full Gradiometer Kit and the Professional 3-Axis Magnetometer Kit.
Role in the System
FG-3+ Sensor(s) ──► MAG-BOARD (ESP32) ──► LCD Display
──► USB / Serial output
──► Optional buttons / LEDs
──► Optional external flash
The MAG-BOARD firmware reads the frequency pulse outputs from connected FG-3+ sensors, computes magnetic field values, and provides real-time readout on an optional LCD display.
Power
The MAG-BOARD does not have reverse-polarity protection. Connecting the power supply with reversed polarity will permanently damage the board. Always verify polarity before connecting power.
- Supply voltage: refer to the MAG-BOARD product page for the required input voltage range
- Use a regulated, low-noise power supply
- Do not power from the same rail as motors or high-current loads without adequate filtering
Optional User Interface Components
The MAG-BOARD supports optional hardware add-ons that can be populated depending on the application:
| Component | Function |
|---|---|
| Push buttons | User input (e.g., mode selection, logging start/stop) |
| LEDs | Status indication (e.g., power, logging, GPS fix) |
| LCD display | Real-time magnetic field readout |
These components are connected to designated pads or connectors on the board. Refer to the assembly instructions in the Full Gradiometer Kit documentation for placement details.
LCD Voltage Selection
The MAG-BOARD includes a voltage selection jumper or solder bridge for the LCD backlight and logic supply. This must be set correctly for your specific LCD module:
- 3.3 V — for 3.3 V LCD modules
- 5 V — for 5 V LCD modules
Setting the wrong LCD voltage can damage the LCD module or cause it to fail to initialize. Verify your LCD's supply voltage before selecting.
Optional External Flash
The MAG-BOARD includes a footprint for an optional external SPI flash memory chip. This allows firmware to store calibration data, configuration, or extended log buffers locally on the board.
External flash is not required for standard operation. It is an optional feature for advanced use cases.
Firmware
The MAG-BOARD runs custom firmware developed by FG Sensors. Two flashing workflows are supported:
Arduino IDE
The MAG-BOARD is compatible with the Arduino IDE via the ESP32 board support package.
- Install the ESP32 board package in Arduino IDE
- Select the appropriate ESP32 board variant
- Open the MAG-BOARD sketch
- Connect via USB and upload
See the Programming the MAG-BOARD guide for detailed step-by-step instructions.
BIN File Flashing (ESP32 Flash Download Tool)
Pre-compiled firmware in .bin format can be flashed directly using the ESP32 Flash Download Tool:
- Download the ESP32 Flash Download Tool from Espressif
- Connect the MAG-BOARD via USB
- Select the chip type (ESP32)
- Load the firmware
.binfile at the correct flash address - Click Start
This method does not require the Arduino IDE and is recommended for updating firmware without modifying code.
See the Firmware Installation guide for detailed instructions and download links.
Serial Output
When connected via USB, the MAG-BOARD presents as a USB-UART bridge. The serial output provides real-time magnetic field measurements and is readable by any serial terminal or host software.
| Parameter | Value |
|---|---|
| Interface | USB (via onboard USB-UART) |
| Baud rate | Refer to firmware documentation |
| Format | Text / ASCII |